J. Phys. IV France 112 (2003) 523
Stabilization of martensite in microstructure of a Cu-Zn-AI shape-memory alloyS. Longauer, M. Vojtko, G. Janak and M. Longauerova
Department of Materials Science, Faculty of Metallurgy, Technical University of Kosice, Letna 9, 04200 Kosice, Slovak Republic
Direct quenching of samples of Cu22Zn4.6A1 alloy from temperatures of an -field to room temperature causes strong stabilization of martensite in samples with A (the temperature at which transformation to austenite begins) above room temperature. This can be removed by immediate heating of samples at 170°C after quenching from T between 630 and 690°C. Shift of A to the nominal value depends on time of annealing. In samples quenched from higher temperatures over 690°C the stabilization was not removed. The observation of in situ deformation of martensite in upquenched samples supports the explanation  of the decreasing shape memory with increasing quenching temperature by changes in stacking fault energy.
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